Layer wound inductance coil



Nov. 2, 1965 5. J. SUBIK 3,2

LAYER WQUND INDUCTANCE COIL Filed June 4, 1962 INVENTOR STEVEN J. SUBIK,

IS ATTORNEY.

United States Patent 3,215,965 LAYER WOUND INDUCTANCE COIL Steven J.Subik, North Syracuse, N.Y., assignor to General Electric Company, acorporation of New York Filed June 4, 1962, Ser. No.199,727

1 Claim. (Cl. 336-408) This invention relates to layer wound inductancecoils and more particularly to an improvement in layer wound inductancecoils for facilitating the manufacture of such coils.

- Layer wound inductance coils find advantageous use in manyapplications. Because of their reduced cost relative to the cost ofpancake type coils having a universal Winding, the layer wound coil hasrecently replaced the former type coil as the tertiary winding in thehorizontal output transformer in some television receivers.

V For this and other similar applications, a known economicalarrangement of the layer wound coil comprises a narrow tubular pressedpaper coil form having a continuously wound coil of relatively finepolyurethane insulated wire, such as No. 36 AWG gage, wound thereupon.The coil is arranged in multiple relatively narrow layers having aplurality of turns of wire in each layer. The'layers are radiallydisposed from a longitudinal axis of the form and an insulating medium,such as a strip of paper, is positioned between each of the layers. Theassembled coil, as described, resembles a thin disk.

' A manufacturing difiiculty is experienced when layer .wound coils ofthe type described are machine fabricated in quantity. In onemanufacturing arrangement, a plurality of coils are simultaneously woundside by side upon a single tubular coil form. The individual built upcoils are subsequently separated by a cutting operation. An initial turnof fine wire of each coil, which is a terminal lead for the coil, laysadjacent to the form and is buried by the successively wound layers andburrs created on the form by the cutting operation. Prior attempts forrecovering this lead have consisted in wedging a tool between the formand a first insulating paper layer and A further object of thisinvention is to provide a layer I wound inductance coil in which aburied initial turn of wire representing a terminal lead may be easilyvrecovered from beneath successively wound layers.

In accordance with the present invention, a layer wound coil is providedhaving a coil form and a coil of relatively fine insulated wire which iscontinuously wound upon the form in a plurality of radially disposedinsulated layers. A pair of terminal leads for the coil consists of aneasily accessible end turn on an outer layer of the coil and aninitially wound turn of the coil which is buried by the coil layers. Thecoil form includes an access passageway to the buried turn forpermitting insertion of a tool for grappling and leading out the buriedturn to a point without the coil.

In one embodiment of the present invention, a tubular coil form isprovided having a longitudinal groove in an outer surface of the form. Afirst turn is helically wound in a longitudinal direction upon the formand traverses the groove in the surface. A segregating medium forfacilitating grappling of the lead is positioned on the turn in the areaof the groove intermediate the lead and successively wound turns of thecoil.

Patented Nov. 2, 1965 Further objects, features and the attendingadvantages of the invention will be apparent with reference to thefollowing specification and drawings in which:

FIGURE 1 is a perspective view of an automatic coil winding machine forwinding layer wound coils,

FIGURE 2 is a front view of a conventional layer wound coil which hasbeen wound on the machine of FIGURE 1,

FIGURE 3 is a side view of the coil of FIGURE 2,

FIGURE 4 is a front view of a coil form utilized in an embodiment of thepresent invention,

FIGURE 5 is a side view of the form of FIGURE 4,

FIGURE 6 is a side view of a fabricated coil embodying the presentinvention,

FIGURE 7 is an enlarged front view of a coil form illustrating featuresof the present invention, and

FIGURE 8 is a side view of the form of FIGURE 7.

In order that the features of this invention may be fully appreciated,the fabrication of a layer wound coil of the type referred to will bebriefly described with reference to FIGURE 1. In the manufacturingarrangement illustrated therein, a tubular stock 11 of pressed paperhaving a suitable length for fabricating a plurality of coil formstherefrom is mounted horizontally intermediate drive and supportmandrels 12 and 13 on a bed 14 of a coil winding machine 15. A pluralityof spools of wire, not shown, are stationed relative to the, machine forproviding the necessary wire 16 for simultaneously winding individualcoils 17 at equally spaced positions along the stock. A wire guidemechanism consisting of a support structure 18 and having multiple wireguides 19 positioned on a cross bar 20'for feeding wire to and guidingthe winding of the coils 17 is positioned on a track 30. The support 18is driven with a slow reciprocating motion along the track by means,such as a rotating screw driven shaft, not shown. In addition, anapparatus for automatically measuring, cutting, and inserting a strip ofinsulating paper between successively wound layers of the coils beingfabricated is provided. For purposes of clarity, FIGURE 1 illustratesonly a cutting table 31, two cutting blades 32 and 33 and a strip ofpaper 3 being fed to the apparatus.

In operation, a tubular stock is mounted between the mandrels 12 and 13and a lead wire 16 from each spool of wire is initially secured atequally spaced positions along the stock by an adhesive medium.Sufficient spacing is provided between immediately adjacent positionsfor permitting the build up of a desired width of the coils and forallowing subsequently assembled coils to be separated by a cuttingoperation without damaging the fabricated windings. The stock 11 isautomatically rotated .about its axis by the drive mandrel 12 having aprime mover not shown, while the wire guide is simultaneously drivenparallel to the axis of the stock, by a prime mover not shown, forcausing a single layer of a desired number of turns to be wound at eachcoil position. When a layer has been wound, a strip of insulating paperhaving a width equal to the length of the stock is automaticallymeasured, cut from the strip 34, and positioned on the stock. The wireguide then reciprocates and a succeeding layer for each coil is woundupon the insulating paper as each of the wires 16 traverse the stock 11in the opposite direction. The described winding operation is thensuccessively repeated until a desired layer wound coil configuration hasbeen built up. Each loose coil end-lead is taped to its coil body andthe wires 16 are then severed. The entire assembly is removed and theindividual coils are separated from the assembly by cutting the assemblyin a plane perpendicular to the longitudinal axis of the stock.

A single coil 35 which has been manufactured by the above describedprocedure is shown in the views of FIG- URES 2 and 3. The coil 35includes a form 36, the built up layers of wire and insulating paperswhich are radially disposed from a longitudinal axis 37 of the form, anouter layer of wire turns 38, a terminal lead 39, and a strip of tape 40which secures the lead 39. In order to satisfy a variety ofrequirement-s, namely, to provide structural coil support, to providethe desired electrical characteristics for the coil, and to provide thenecessary clearance for severing individual coils from the abovedescribed assembly, the width of the assembled coil 41 is generallygreater than the width of each layer of turns 42. Consequently, theinitial turn of fine wire 16 which constitutes a terminal lead for thecoil 35 and which was secured to the stock 11 on the winding machine 15is buried beneath the multiple layers of insulating paper and wire turnsand behind a flared edge of the form created by the cutting operation. Apressure exerted on an outer surface 43 of the form by the successivelybuilt up layers of paper and wire turns makes this turn relativelyinaccessible and difiicult to retrieve. As previously indicated, priorattempts at recovering the buried lead have consisted in wedging a toolbetween the outer surface 43 of the form and an adjacent layer of paperand turns 44 and probing for the hidden lead.

In accordance with a feature of the present invention, a coil form isprovided for the coil which includes access to the buried lead for agrappling tool. FIGURES 4 and illustrate a coil form 50 for a singlecoil having a longitudinal groove 51 in a thickness of the form andwhich communicates with the outer surface 52 of the form. FIG- URE 6illustrates an assembled coil 53 of the-type described embodying theinvention. A grappling tool may be inserted in the groove 54 of the coil53 to recover the buried lead in a minimum amount of time and withoutcausing damage to the coil. The coil 53 may be conventionallymanufactured by the above described procedure by providing the stock 11of FIGURE 1 with a groove extending longitudinally on the length of thestock.

In accordance with another feature of this invention, a segregatingmeans is provided for facilitating the grappling of the desired hiddenlead without interfering with other turns of the coil. Referring toFIGURES 7 and 8, a single coil form is shown having a groove 55 and thefirst two and one-half turns of a coil wound upon the form. Asegregating means 56, which may consist of an adhesive tape preferablyhaving an adhesive surface positioned away from the surface of the form,is positioned between a length of lead wire 57-58, which is drawn alongthe lower surface of medium 56 until a portion of wire 57-58 is graspedwithout interfering with i or grasping other turns of the coil.

In accordance with another feature of this invention,

the initial lead length 57-58 is wound helically along the surface ofthe form 55 in the direction of the longitudinal axis 60 of the form.Thus, when a grappling tool is inserted in the groove 55 from side 61 ofthe form, wire section 62 will first be contacted and the entire lead57-58 is retrieved by pulling wire section 62. This is more advantageousthan first. grappling a segment 63 of wire lead 57-58, in that thenecessary operator motions for recovering the entire lead areconsequently reduced.

The above described features may be incorporated into the automatic coilwinding procedure which was described hereinbefore by utilizing a stock11 with a groove running longitudinally for its length, already referredto, by taping the lead wires 16 on an outer surface of the stock 11 atan angle 6 from the groove as indicated in FIGURE 8 and in FIGURE 7 bythe tape 64, by winding two and one-half turns of lead wire or as manyturns as are necessary to provide a desired lead length, and by thenpositioning an insulating medium over the groove and securing it by anyconvenient method, as by winding additional turns over it to secure itin place.

Although I have described the present invention with relation to apressed paper coil form, other coil form material may be utilized andincorporate the invention. For example, the coil form may consist ofphenolic or plastic and the slot 51 indicated in FIGURE 5 may beincorporated into the form during a molding fabrication process.

While I have illustrated and described and have pointed out in theannexed claim certain novel features of my invention, it will beunderstood that various omissions, substitution-s and changes in theforms and details of the system illustrated may be made by those skilledin the ,art without departing from the spirit of the invention andthescope of the claim.

What I claim as new and desire to secure by Letters Patent of the UnitedState-s is:

An inductor comprising: a cylindrical tubular paper coil support elementhaving an outer surface, said outer surface having a groove extendinglongitudinally in the surface; a coil of relatively fine insulated wirewound upon said support element, said coil comprising an initial turnwound adjacent to said surface and transverse to said groove andsucceeding turns wound in insulated radially disposed layers, means forseparating a segment of said initial turn from succeeding turns in thearea of said groove comprising a strip of insulating material positionedupon said initial turn intermediate said initial and succeeding turnsand covering a surface area of said support including said groovewhereby said initial turn may be retrieved from said coil through saidgroove .to form a terminal lead.

References Cited by the Examiner UNITED STATES PATENTS 644,311 2/00Anderson 336-192 X 2,122,894 7/38 Sager 336-192 2,166,841 7/39 Helgas-onet al 336-l92 2,859,000 11/58 McLellan 242-125.2 2,985,950 5/61 Du-man29155.57

' 2,999,990 9/61 Zack 336-208 JOHN F. BURNS, Primary Examiner.

